Why did my mesh disappear after using remesh modifier?
For this modifier object has to be a 3D. Your N is only 2D. 

To clean up go to edit mode, select all vertices and press X > Limited Dissolve. 



Or select all vertices and press F (Make Face)

For more info https://docs.blender.org/manual/en/latest/modeling/meshes/editing/basics/deleting.html